Chandler Carruth 9b2d091a9c [InstCombine] Do an about-face on how LLVM canonicalizes (cast (load ... ...)) and (load (cast ...)): canonicalize toward the former. Historically, we've tried to load using the type of the *pointer*, and tried to match that type as closely as possible removing as many pointer casts as we could and trading them for bitcasts of the loaded value. This is deeply and fundamentally wrong. Repeat after me: memory does not have a type! This was a hard lesson for me to learn working on SROA. There is only one thing that should actually drive the type used for a pointer, and that is the type which we need to use to load from that pointer. Matching up pointer types to the loaded value types is very useful because it minimizes the physical size of the IR required for no-op casts. Similarly, the only thing that should drive the type used for a loaded value is *how that value is used*! Again, this minimizes casts. And in fact, the *only* thing motivating types in any part of LLVM's IR are the types used by the operations in the IR. We should match them as closely as possible. I've ended up removing some tests here as they were testing bugs or behavior that is no longer present. Mostly though, this is just cleanup to let the tests continue to function as intended. The only fallout I've found so far from this change was SROA and I have fixed it to not be impeded by the different type of load. If you find more places where this change causes optimizations not to fire, those too are likely bugs where we are assuming that the type of pointers is "significant" for optimization purposes. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220138 91177308-0d34-0410-b5e6-96231b3b80d8		2014-10-18 06:36:22 +00:00
..
Analysis	[LVI] Add some additional comments about caching and context instructions	2014-10-16 00:40:05 +00:00
AsmParser
Bitcode	correct const-ness with auto and dyn_cast	2014-10-15 17:45:13 +00:00
CodeGen	Check for dynamic alloca's when selecting lifetime intrinsics.	2014-10-17 22:59:33 +00:00
DebugInfo	Add couple of missing 'override' keyword. NFC.	2014-10-10 17:34:30 +00:00
ExecutionEngine	[MCJIT] Replace memcpy with readBytesUnaligned in RuntimeDyldMachOI386.	2014-10-10 23:07:09 +00:00
IR	[Stackmaps] Enable invoking the patchpoint intrinsic.	2014-10-17 17:39:00 +00:00
IRReader
LineEditor
Linker
LTO
MC	Add back commits r219835 and a fixed version of r219829.	2014-10-17 01:48:58 +00:00
Object	[llvm-objdump] Fix mach-o binding decompression error	2014-10-18 01:21:02 +00:00
Option
ProfileData	Reduce double set lookups. NFC.	2014-10-10 15:32:50 +00:00
Support	Introduce LLVMParseCommandLineOptions C API function.	2014-10-16 22:47:52 +00:00
TableGen	Eliminate some deep std::vector copies. NFC.	2014-10-03 18:33:16 +00:00
Target	R600/SI: Add global atomicrmw xchg	2014-10-17 23:33:03 +00:00
Transforms	[InstCombine] Do an about-face on how LLVM canonicalizes (cast (load	2014-10-18 06:36:22 +00:00
CMakeLists.txt
LLVMBuild.txt
Makefile